My 2B is s/n 2974 and it uses an 8BN8. May 1961 is printed on the S-meter rear cover.
Food for thought: if all of the filaments were floating, instead of being grounded on one side, would this 'rectified' hum problem manifest itself?
Maybe not, but production would be a bit more labour intensive. Drake employed bean counters too.73.
Ken, VE3FIT
